Purpose The purpose of this experiment is to introduce several of the tools, techniques, and skills necessary for work in the analytical chemistry laboratory. The techniques are considered one at a time, as unit operations. It is important to learn proper techniques and to acquire individual skills before attempting additional laboratory experiments. The two experiments focused on the use of an analytical balance and calibrating a pipet. The overall objective is to acquire the skills to use the analytical balance accurately and to develop the proper manual technique for calibrating an analytical transfer pipet with practice and attention to detail. Materials • 5 pennies • Distilled water • Analytical balance • Analytical pipet • Thermometer • Volumetric glassware • Erlenmeyer flask • Tweezers • Calculator Procedure 1. After you have been instructed in the use of the balance and have become familiar with its use, obtain a set of pennies, an unknown aluminum cylinder, and a pair of tweezers from the instructor. 2. Do not handle the pennies or the cylinder with your fingers; always use the tweezers. If you are using a mechanical balance, be sure to have the balance in the “off” or “complete arrest” position whenever removing anything from or adding anything to the balance pan. 3. Before you begin to determine masses, zero your analytical balance carefully. Select five pennies at random from the vial containing the pennies, and weigh each penny on your balance. Enter the data in your laboratory notebook. Keep track of the identity of each penny by placing each one on a labeled piece of paper.

This is the end of the preview. Sign up
to
access the rest of the document.